GB1227637A - - Google Patents

Abstract

1,227,637. Controlling winches. HARNISCHFEGER CORP. 1 Oct., 1969 [10 Oct., 1968], No. 48147/69. Heading B8B. [Also in Division F2] The control means for a power transmission mechanism of a truck crane comprises a pair of levers 22, 23 which are each swingable to control through hydraulic valves 26 or 27, an associated clutch 26b, 27b on hoist drums 8, 9, each lever being provided with a twist grip which through a cam device linearly actuates a cable 34 to modulate through an hydraulic value 42, a torque converter TC controlling the drive speed to the drums 8, 9. The converter TC is driven from a modulatable clutch MC at one end of a power unit E. Each valve 26, 27 normally in a spring maintained neutral position in which pressure fluid from a pump P<SP>1</SP> is passed through the valve to reservoir, is operable by the levers 22, 23 to vary the hydraulic actuating pressure for the drum clutches 8a, 9a. The speed of drive to these clutches is controlled by simultaneous actuation of the valve 42 controlling the fluid supply to the torque connecter through a reduced charging pressure valve 46, the fluid for the valve 42 being supplied from an independent circuit including a pump P. The friction plate clutch MC is modulatable by a centrifugally operated valve 51 controlling fluid supply to the clutch direct from the pump P. The output shaft from the torque connecter is coupled to a manually settable governor which is hydraulically coupled to the valves 46 and 51. The power unit E drives from its other end, a transmission 12, 13 coupled to a clutch controlling the crane boom hoist and to a pair of electro-magnetic clutches 15, 16 controlling swinging of the boom.